15. Shading effect of multipurpose trees on growth and yield of Boro rice cv. BRRI dhan29

Abstract

A field experiment was conducted during Rabi season (December-May) to compare the vegetative growth and yield of Boro rice cv. BRRI dhan29 under tree shade and ambient (shade free) condition in Boira village at Sadar upazila of Mymensingh district. In this study, twelve years old Mango (Mangifera indica), eight years old Mahogany (Swietenia macrophylla) and ten years old Sissoo (Dalbergia sissoo) trees were selected as treatment and each of the tree had six replications. The experiment was laid out in a two factorial Randomized Complete Block Design (RCBD). To achieve the objective, the parameters reflect on growth, yield and yield contributing characters were recorded at different stages of rice plants under both tree shade and ambient condition. The result showed that different treatments significantly influenced on the growth and yield contributing components viz. plant height, effective tillers hill^-1, leaf number hill^-1, leaf area hill^-1, panicle length, filled spikelet’s panicle^-1 and grain yield. The maximum (5.20 tha^-1, 7.65 tha^-1 and 13.20 tha^-1) grain yield, straw yield and biological yield of rice was produced in the Mango ambient condition
and the minimum (1.68 tha^-1 ) grain yield in the Mango tree shade and straw yield and biological yield (3.64 tha^-1 and 5.93 tha^-1) was produced in the Mahogany tree shade area. The highest (43.87%) harvest index of rice was recorded in Mahogany tree ambient area and the lowest (24.94%) in Mango tree shade area. From the above results, it was found that maximum (68%) reduction of rice grain yield was recorded under Mango tree shade, moderate (28%) under the shade of Mahogany tree where as no rice grain yield reduction was occurred in Sissoo tree shade and ambient condition. Therefore, it can be concluded that
in consideration of shade casted by different trees, Sissoo-Boro rice and Mahogany-Boro rice based agroforestry systems is suitable in second case although there was some yield loss (28%) compare to Mango-Boro rice agroforestry system.